title: Near-infrared spectroscopy monitoring of the collateral network prior to, during, and after thoracoabdominal aortic repair: a pilot study.
abstract: OBJECTIVE
  The aim of this study was to evaluate the feasibility of non-invasive monitoring of the paraspinous collateral network (CN) oxygenation prior to, during, and after thoracoabdominal aortic repair in a clinical series.
  
  
  METHODS
  Near-infrared spectroscopy optodes were positioned bilaterally-over the thoracic and lumbar paraspinous vasculature-to transcutaneously monitor muscle oxygenation of the CN in 20 patients (age: 66 ± 10 years; men = 11) between September 2010 and April 2012; 15 had open thoracoabdominal aortic repair (Crawford II and III), three had thoracic endovascular aortic repair (TEVAR; Crawford I), and two had a hybrid repair (Crawford II). CN oxygenation was continuously recorded until 48 hours postoperatively.
  
  
  RESULTS
  Hospital mortality was 5% (n = 1), 15% suffered ischemic spinal cord injury (SCI). Mean thoracic CN oxygenation saturation was 75.5 ± 8% prior to anesthesia (=baseline) without significant variations throughout the procedure (during non-pulsatile cooling on cardiopulmonary bypass and with aortic cross-clamping; range = 70.6-79.5%). Lumbar CN oxygenation (LbS) dropped significantly after proximal aortic cross-clamping to a minimum after 11.7 ± 4 minutes (74 ± 13% of baseline), but fully recovered after restoration of pulsatile flow to 98.5% of baseline. During TEVAR, stent-graft deployment did not significantly affect LbS. Three patients developed relevant SCI (paraplegia n = 1/paraparesis n = 2). In these patients LbS reduction after aortic cross-clamping was significantly lower compared with patients who did not experience SCI (p = .041).
  
  
  CONCLUSIONS
  Non-invasive monitoring of CN oxygenation prior to, during, and after thoracoabdominal aortic repair is feasible. Lumbar CN oxygenation levels directly respond to compromise of aortic blood circulation.
authors.affiliation: Department of Cardiac Surgery, University of Leipzig, Heart Center Leipzig, Saxony, Germany; Department of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, NY, USA. Electronic address: christian.etz@med.uni-leipzig.de.
authors.forename: C D
authors.initials: CD
authors.lastname: Etz
authors.forename: K
authors.initials: K
authors.lastname: von Aspern
authors.forename: S
authors.initials: S
authors.lastname: Gudehus
authors.forename: M
authors.initials: M
authors.lastname: Luehr
authors.forename: F F
authors.initials: FF
authors.lastname: Girrbach
authors.forename: J
authors.initials: J
authors.lastname: Ender
authors.forename: M
authors.initials: M
authors.lastname: Borger
authors.forename: F W
authors.initials: FW
authors.lastname: Mohr
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000601:surgery; D001013:Aorta, Thoracic / Q000601:surgery; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation; D003097:Collateral Circulation; D057510:Endovascular Procedures; D005240:Feasibility Studies; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007511:Ischemia / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D018482:Muscle, Skeletal / Q000098:blood supply; D010264:Paraplegia / Q000209:etiology / Q000517:prevention & control; D010291:Paresis / Q000209:etiology / Q000517:prevention & control; D010865:Pilot Projects; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control; D019265:Spectroscopy, Near-Infrared; D013116:Spinal Cord / Q000098:blood supply*; D015607:Stents
keywords: Collateral network; NIRS; Non-invasive monitoring; Spinal cord ischemia; Spinal cord protection; TEVAR; Thoracoabdominal aortic repair